Carleton University
Department of Electronics
ELEC4600
Radar and Navigation Engineering
M.R. Edwards
Quiz #3
(1 page of questions + 2 pages of equations+6 pages of graphs)
2007
Data:
1 NM = 1.151 mi. = 1852 m
Boltzmann’s constant k = 1.38 x 10-23 J/
System temperature T0 = 293 K
c = 3 x 108 m/s
1. <6 marks> A Radar has a peak output of 1.5 MW, the carrier frequency is 1.5GHz and the antenna
effective area is 30 m2. A target is detected at a range of 30 km and results in a peak power out of the antenna
of 10nW.
What is the radar cross section of the target?
2. <17 marks> A 1.5 GHz surveillance radar is required to have a range of 150 nautical miles for large, high
altitude commercial aircraft (ave = 75 m2, Swerling 4), a single pulse P d = 90%, and a single pulse Pfa = 10-4.
The transmitter provides a peak power of 150 kW with a pulse width of 1.5s; the antenna provides a gain of
29 dB ; the receiver has a noise figure of 3 dB and the total losses are 5 dB.
PRF is 518 Hz and antenna rotation rate is 12 rpm.
(a)
Show that 17 pulses must be integrated to achieve the required performance.
(b)
What antenna azimuth beamwidth will be required?
(c)
With the azimuth beamwidth of ii, what is the vertical beamwidth?
3. <4 marks> Suggest two methods of reducing the radar cross section of an aircraft.
4. <3 marks> Arrange the following objects in descending order of radar cross section. i.e. largest first
(a)
Sphere
(b)
Cone (point toward radar)
(c)
Corner cube
5. <7 marks> During the maintenance of a radar someone neglected to tighten the bolts of a connector
resulting in an increase of 6dB in plumbing loss. By what percentage was the range of the radar reduced as a
result?
BONUS
6. <5 marks> Show that, if an object reflects incident radiation back towards the transmitter uniformly into a
solid angle of  (rad2) then the radar cross section of the object is 4/ times the physical cross section.